1. Field of the Invention
This invention relates generally to archery bows and, more particularly, to an adjustable cam for an archery bow.
2. Description of the Related Art
Compound archery bows are well known and may utilize one or more cams to more efficiently store energy in the bow limbs as a drawstring of the bow is drawn. Additionally, a compound bow provides a let-off or reduction of the force required to pull the drawstring during a portion of the draw, and may be adapted to limit the maximum draw length of the bow. Both improve the performance and ease of use of the bow. Compound bows may utilize a single cam and an idler wheel on opposed limbs of the bow or a pair of cams, one at the free end of each limb of the bow.
Some archery bows utilize one-piece unitary cams that have one or more grooves formed therein to receive the strings of the bow and one or more posts to which the free end of a bowstring may be attached. To change the characteristics of the bow, such as the draw length, location in the draw and intensity of the let-off of the draw, the user of the bow must completely disassemble the bow and replace the existing cams with replacement cams having different characteristics. Notably, the bow must be disassembled with the use of a bow press to safely remove the bowstring from the limbs which are all under tension. After changing, the cams, the bow must be reassembled and readjusted to enable and optimize its use with the new cams. Further, the new cams are just as inflexible as the old cams in that they have fixed characteristics that cannot be readily altered by a user. Thus, the one-piece cams are very limited, difficult and expensive to change, and very costly to manufacture as several distinct cams must be manufactured for the various draw lengths and let-offs desired by consumers.
So-called modular cams have also been used on archery bows. These modular cams have a one-piece main body as in prior cams, and a plurality of individual modules which can be mounted one at a time onto the cam body with each having a different shape and hence, different characteristics in use. Each individual module is distinct from one another and may be individually fixed to the cam in a single location to provide the desired characteristics to the cam and hence the archery bow. For example, modules having different profiles or contours may be placed on a cam to change the intensity of the let-off, which is usually stated as a percent of the draw weight, or the location in the draw where the let-off is initiated. Thus, to vary the let-off within a range of intensity of let-offs, a plurality of independent and distinct modules must be used.
Additionally, to limit the draw length of the bow, some cams have been adapted to receive "draw stops" which engage either a string or a limb of the bow at the maximum draw length of the bow to prevent the bow from being overdrawn. Conventional draw stops are typically small knobs attached to the cam by a screw. Such draw stops may vibrate loose from the cam and be lost during use. Still further, the engagement of the small knob with the limb or a bowstring provides a very abrupt stop and a "jerky," unsmooth feel to the bow that is undesirable to consumers. Still further, movement of the draw stop relative to the cam, or to a module on the cam, can undesirably change the performance, efficiency and accuracy of the bow. An incorrectly placed draw stop can reduce the efficiency of the bow, cause a loss in accuracy of an arrow shot from the bow and result in a decrease in speed of an arrow shot from the bow.